The looking glass was an important tool for Lucian Freud, but his work went far beyond mirror-play. As an exhibition of his portraits opens, his biographer and friend writes about his ruthless, confrontational realism

John Martin, the most popular painter of his day, specialised in vast canvases of the ancient world in chaos – the plagues of Egypt, the destruction of Pompeii … Neglected for decades, writes
William Feaver, his spectacular art is regarded highly once more

When he was found hanged in his shed at the age of 46 – or was it 44? – Arshile Gorky, a master or reinvention, was perhaps the greatest painter in America. His death left the field open for his rival Jackson Pollock, says William Feaver

Constable's landscape sketches were like diary entries, reflecting his mood at the time. He then worked them up into epic paintings fit for exhibition. It is this development that makes his work so exhilarating, writes William Feaver.

Lucian Freud's latest painting, Eli and David, will shortly appear alongside the work of his friend Frank Auerbach. But should they hang beside Constables and Turners? Curator William Feaver explains his decision.